Question

How much pure alcohol must be added to 400 ml of a 15% solution to make its strength 32% ? how to solve this question

Answer 1

Let the required number of milliliters of alcohols be x ml.

Given 15 % of 400 ml should be added with 100 % of pure alcohol.

Hence 400(15 %) + x(100 %) = (400+x) (32 %)

⇒ 400 × 15/100 + x = (400 + x) × (32/100)

⇒ 60 + x = 128 + (8x/25)

⇒ x - 8x/25 = 128 - 60

⇒ 17x/25 = 68

⇒ x = (68 × 25)/17

⇒ x = 1700/17

x = 100 ml   Answer

Answer 2

400ml has 15% of alcohol that is 60 ml which means we have 340 ml of water or liquid with which alcohol is mixed me be the volume of alcohol added to make the strength of 32 percentage then v/ 340 + v =to 32/ 100 solving this we get v

as 160 ml

so we need to add 160 - 60 =100 ml of alcohol.